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cdl > Combination Vehicles > Flashcards

Combination Vehicles Flashcards

1
Q

Where should tractor be when you inspect landing gear after uncoupling the trailer?

A

With the tractor frame under the trailer

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2
Q

While driving behind another vehicle under good conditions you should allow at least one second between your vehicle and the vehicle ahead for each ____ (how many) feet of your vehicle length?

A

10

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3
Q

There are two things that a driver can do to prevent a rollover. They are: (1) keep the cargo as close to the ground as possible; and (2):

A

Go slow around turns

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4
Q

The air brake leakage rate for a combination vehicle (engine off, brakes off)should be less than ___ psi per minute.

A

3

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5
Q

The safest way to make a turn without entering another traffic lane is:

A

You should turn wide as you complete the turn

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6
Q

The higher the center of gravity of your truck, the:

A

Easier to turn over

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7
Q

If the service line comes apart while you are driving a combination vehicle but the emergency line stays together, what will hapen right away?

A

Nothing is likely to happen until you try to apply the brakes.

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8
Q

Glad hands are usually connecting which lines?

A

Service and emergency air lines from the vehicle to the trailer

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9
Q

A driver crosses the air lines when hooking up to an old trailer, what will happen?

A

If the trailer has no spring brakes, you could drive, but you wouldn’t have trailer brakes

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10
Q

The hand valve should be used

A

To test the trailer brakes

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11
Q

When driving a set of doubles it is necessary to close which shut-off valve in the last trailer?

A

Back

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12
Q

If the service line comes apart while you are driving a combination vehicle but the emergency line stays together, what will happen right away?

A

Nothing is likely to happen until you try to apply the brakes

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13
Q

You are about to back your tractor under a semi-trailer. The trailer is at the right height when the:

A

Trailer will be lifted slightly when the tractor backs under it

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14
Q

Your emergency air line breaks or gets pulled apart while you are driving. The loss of pressure will cause the:

A

Emergency trailer brakes to come on

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15
Q

If the brakes did not release when you pushed the trailer air supply valves you should:

A

Check air line connection

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16
Q

Air brake equipped trailers made before 1975:

A

Often do not have spring brakes

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17
Q

There are two things that a driver can do to prevent a rollover, (1.) go slow around turns, and (2.)

A

Keep the cargo as close to the ground as possible

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18
Q

After connecting the air lines, but before backing under the trailer you should

A

Supply air to the trailer system, the pull the air supply knob.

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19
Q

Which part of the kingpin should the locking jaws close around?

A

The shank

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20
Q

How much space should be allowed between upper and lower fifth wheel after coupling?

A

Nothing

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21
Q

You have pushed the trailer air supply valve. You should not back a tractor under a trailer until the whole air system is

A

At normal pressure

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22
Q

You are coupling a tractor to a semi-trailer. You have conected the airline. Before backing under the trailer you should

A

Supply air to the trailer system, then pull out the air supply knob

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23
Q

You are coupling a tractor to a semi-trailer and have backed up but are not under it. What should you hook up before backing under?

A

The emergency and service lines

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24
Q

Tractor with a _______ trailer requires the shortest amount of stopping distance.

A

Fully loaded

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25
Q

After you have couple the trailer you should raise the landing gear by using

A

Low gear

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26
Q

You supply air to the trailer tanks by

A

Pushing in the trailer air supply valve

27
Q

Why should you be sure that the fifth wheel plate is greased as required?

A

To prevent steering problems

28
Q

When connecting the glad hands, press the two seals with the coupler together at what degree to each other?

A

90 Degrees

29
Q

Which of these statements is true?

A

Bobtail tractors can take longer to stop than a combination vehicle loaded to maximum gross weight.

30
Q

Why should you lock the tractor glad hands to each other (or dummy couplers) when you are not towing a trailer?

A

It will keep dirt or water out of the lines

31
Q

When backing a tractor under a trailer you should

A

Always use the lowest reverse gear

32
Q

After the trailer has been coupled to the tractor, the tractor protection control valve should be placed in what position?

A

Normal

33
Q

The fifth wheel locking lever is not locked after the jaws close around the kingpin. This means that:

A

The coupling is not right and should be fixed before driving the coupled unit.

34
Q

Off-tracking or cheating causes which of these to follow the wider pass while making a turn?

A

Tractor towing a 45 foot trailer

35
Q

The iron trailer supports are up and the trailer is resting on the tractor. Make sure:

A

There is enough clearance between the tractor frame and landing gear.

36
Q

When you are uncoupling a loaded trailer you should lower the landing gear until it

A

Makes firm contact with the ground, then crank in a low gear a few extra turns.

37
Q

What will happen if the air lines are crossed when you hook up to an old trailer?

A

If the trailer has no spring brakes, you could drive away but wouldn’t have any trailer brakes

38
Q

To stop a trailer skid you should

A

Release the service brakes

39
Q

If you cannot make a turn without entering another traffic lane

A

You should turn wide as you complete the turn

40
Q

The air lines on combination vehicles are often colored to prevent them from mixing up. The emergency line is___, and the service line is ___.

A

Red, Blue

41
Q

The air leakage rate for a combination vehicle (engine off, brakes on) should be less than ___ psi per minute.

A

4

42
Q

Compared to a straight truck or bus there are ___ things to inspect in combination vehicles.

A

More

43
Q

When checking the trailer emergency brakes, the tractor protection control valve should be placed in what position?

A

Emergency

44
Q

In normal driving, some drivers use the hand valve before the brake pedal to prevent a jackknife. Which of the statements is true?

A

It should not be done

45
Q

While checking if the trailer is securely coupled to the trailer, the landing gears should be

A

Slightly raised

46
Q

Air and electrical lines from the tractor to the trailer should be

A

Secured but with enough loop to turn

47
Q

You have a major leak in the service line and you put on the brakes. Service air will escape and cause the

A

Trailer emergency brakes to come on

48
Q

When you get ready to back under a semi-trailer you should line up

A

Directly in front of the trailer.

49
Q

Off-tracking or cheating causes which of these to follow the wider pass while making a turn?

A

Tractor towing a 45 foot trailer

50
Q

After you lock the kingpin into the fifth wheel, you should check the connection by

A

Pulling the tractor ahead gently with the trailer brakes locked

51
Q

When should you use the hand valve to park a combination vehicle?

A

Never

52
Q

You have coupled with a semitrailer. Where should you put the iron trailer supports before driving away?

A

Fully raised with the crank handle secured in its bracket.

53
Q

The safety catch for the fifth wheel locking lever must be ____ for a coupling to be complete.

A

Over the locking lever

54
Q

After you supply air to the trailer, make sure the air lines are not crossed and the trailer brakes are working. This is done by

A

Applying and releasing the trailer brakes and listening for the sound of the brake

55
Q

Before you back under a trailer, make sure that

A

The trailer brakes are locked

56
Q

How should you test the tractor-semi-trailer connection for security?

A

Pull gently forward in low gear against the locked trailer brakes then look at it carefully.

57
Q

The front trailer supports are up and the trailer is resting on the tractor. Make sure

A

There is enough clearance between the top of the tractor tires and nose of the trailer and that there is enough clearance between the tractor frame and the landing gear

58
Q

To unlock the fifth wheel the locking lever should be placed in the ____ position.

A

Open

59
Q

The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in the ____ brake line

A

Emergency

60
Q

When coupling, the proper position of the fifth wheel is

A

Tilted down towards the end of the trailer

61
Q

What gear should the tractor engine be in after you uncouple the trailer and are inspecting the trailer supports?

A

Neutral

62
Q

When uncoupling the trailer, after you shut off the trailer air supply and lock the trailer, you should:

A

Back up gently to ease pressure on the fifth wheel

63
Q

You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You expect the trailer brakes to come on and

A

The tractor protection valve to close

cdl (2 decks)

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